“Greet each day with a fresh mood” (from “Day Trading”)

“We must not only forget past failures, or more precisely the disappointment from failure, but also acquire the ability to apply only the lessons learned from them.” Are they saying that we should take away lessons from failures and discard the feeling of disappointment?

Negative emotions such as fear, anger, and despair accumulate and may put the mind in an unhealthy state. I can kind of understand that. After trading for a week, the garbage of negative emotions piles up so much it seems dirty... cleansing the mind is also important.

I was reminded of a similar nuance in a scene from “Attack on Titan.” Commander Erwin of the Survey Corps tells Levi, who caused the death of his comrades by his own decisions.

“Stop. Do not regret. The memory of regret dulls your next decision. And you will begin to rely on others to decide. If that happens, you will only have death left. The outcome is not known to anyone. A single decision only makes sense when used as material for the next decision. Continue with the investigation outside the walls.”

I sometimes think, “If only I had done it then, I would be making a lot more money now...” and it lingers in memory for a while. The negative emotion of regret also seems dangerous.